About 30 mins after my last fruitless call. The overseas QF call centre actually called me unprompted (that's a first!). They said they could now price the itinerary (correctly as a Oneworld award). That's been done and I've paid the taxes. Now just have to wait for it to be ticketed, which hopefully doesn't have any issues.
Anyways sorry everyone for spamming the chat, but thought I should update to say the issue has been solved (well for now least until I find a flight from HK back to Oz and try to add it

).